• Journal of KIISE:Computer Systems and Theory
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• v.27 no.4
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• pp.373-382
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• 2000

The most important metric in wormhole-routed networks is the start-up latency. In this paper, we present new multicast algorithms that reduce node contention so that multiple multicast messages can be implemented with reduced latency. By exploiting available channels evenly as much as possible, these new algorithms show better performance than the existing multicast algorithms for wormhole 2D systems when multiple multicasts are involved. All algorithms presented are proven to be deadlock-free. A simulation study has been conducted that compares the performance of these multicast algorithms under various situations in a 2D mesh. We show that the overall performance of ours are up to 20% better than the previous studies. We observe that reducing the number of the generated multidestination messages closely related to shorter message latency. These proposed algorithms can be easily extended to 3D mesh systems.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.570-576
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• 2010

This paper presents the use of the Petri Net Method for modeling railway tracks. The Petri Net is defined as having the characteristics of a parallel, asynchronous, distributed, inconclusive, statistical, etc. information handling system and is a graphical mathematical modeling tool to study the specifics of active movement. It's proven use can be seen at the Korean type Light Rail testing tracks where they modelled the Petri Net method using the train track encasing the segment, track, turnout, and platform as a singular factor and even though two trains either travelling in the same or opposite directions on a single test track equipped with a sidetrack can travel with the guarantee that the two will not collide.

• Proceedings of the IEEK Conference
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• summer
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• pp.103-109
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• 2004

In NLP (Natural Language Processing) tasks, the highest difficulty which computers had to face with, is the built-in ambiguity of Natural Languages. To disambiguate it, formerly, they based on human-devised rules. Building such a complete rule-set is time-consuming and labor-intensive task whilst it doesn't cover all the cases. Besides, when the scale of system increases, it is very difficult to control that rule-set. So, recently, many NLP tasks have changed from rule-based approaches into corpus-based approaches with large annotated corpora. Corpus-based NLP tasks for such popular languages as English, French, etc. have been well studied with satisfactory achievements. In contrast, corpus-based NLP tasks for Vietnamese are at a deadlock due to absence of annotated training data. Furthermore, hand-annotation of even reasonably well-determined features such as part-of-speech (POS) tags has proved to be labor intensive and costly. In this paper, we present our building an annotated English-Vietnamese parallel aligned corpus named EVC to train for Vietnamese-related NLP tasks such as Word Segmentation, POS-tagger, Word Order transfer, Word Sense Disambiguation, English-to-Vietnamese Machine Translation, etc.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.359-366
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• 2016

Today's multi-core technology rapidly increases with more and more Intellectual Property cores on a single chip. Network-on-Chip (NoC) is an emerging communication network design for SoC. For efficient on-chip communication, routing algorithms plays an important role. This paper proposes a novel multicast routing technique entitled as Docket NoC (Dt-NoC), which eliminates the need of routing tables for faster communication. This technique reduces the latency and computing power of NoC. This work uses a CURVE restriction based algorithm to restrict few CURVES during the communication between source and destination and it prevents the network from deadlock and livelock. Performance evaluation is done by utilizing cycle accurate RTL simulator and by Cadence TSMC 18 nm technology. Experimental results show that the Dt-NoC architecture consumes power approximately 33.75% 27.65% and 24.85% less than Baseline XY, EnA, OEnA architectures respectively. Dt-NoC performs good as compared to other routing algorithms such as baseline XY, EnA, OEnA distributed architecture in terms of latency, power and throughput.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.103-112
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• 2005

자동화 컨테이너 터미널의 생산성을 향상시키기 위해서는 장치장과 안벽 사이를 오가며 컨테이너를 운반하는 무인유도 차량(Automated Guided Vehicle: AGV)들이 효율적으로 주행하여 제 시간에 필요한 위치에 도착함으로써 연계 작업들의 지연을 최소화하여야 한다, 만일 AGV들이 목적지까지 주행하여야 하는 거리가 길거나 주행 중에 다른 AGV들과의 충돌이나 교축을 피하기 위하여 대기하여야 하는 상황이 빈번히 발생하면 주행 효율이 떨어지게 된다, 주행 경로의 길이를 줄이기 위하여 경로들을 보다 유연하게 설정할 수 있게 허용하면 경로들간의 교차 가능성이 높아져 교통 통제가 어려워지고 결과적으로 충돌과 교착이 발생할 가능성은 높아진다. 특히 교착을 사전에 방지하기 위하서는 문제가 발생할 소지가 있는 영역을 미리 파악하여 일부 영역을 다른 AGV들이 점유하지 못하도록 제한하여야 하는데, 이는 자칫 AGV 주행 공간의 활용도를 떨어뜨릴 수 있다. 또한 교착의 파악과 이를 방지하기 위한 제어는 실시간에 이루어져야 하므로 연산 부담이 상당하다. 본 논문에서는 유연한 주행 경로 설정이 가능하며 주행 공간을 효율적으로 활용할 수 있는 주행 경로 표현법과 충돌 방지 방안을 제안한다. 또한 교착 발생 가능성을 사전에 파악하고 회피(avoidance)하는데 소요되는 연산비용을 줄여 실시간 적용 가능성을 높이기 위하여 교착해결(deadlock resolution)에 기반을 둔 AGV 주행 관리 방안을 제시한다. 본 논문에서 제안하는 방안의 효율성을 시뮬레이션을 통하여 검증해 보았다.

• Journal of the Korean Society for Railway
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• v.10 no.3 s.40
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• pp.365-371
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• 2007

The communication protocol for interface among railway signalling systems is designed and established as national standard in Korean from a few years ago. So the communication link for information transmission among railway signalling system can be a good example of application of this standard. Communication protocol which is standardized among Korean railway signalling is considered to apply information transmission. And we confirmed there is no the states of deadlock of livelock in std. protocol which is applied formal verification which is one of the analytic method for inspection of safety characteristics in the design course of protocol. But the safety of protocol has to necessarily accomplish this normal analysis approach about satisfying requirement matters with such this analytic approach. In this paper we analyzed the safety characteristics of standard protocol for Korean Railway signalling through the requirement matters for safety transmission of railway transmission system which is required in international standard. So through this study we confirm whether it satisfies safety requirement matters of the level which require in international standard and tried to confirm whether standard protocol has enough safety character in the real railway field.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.1
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• pp.31-40
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• 2021

The important goal of the unmanned vehicle technology is on controlling the direction and speed of the vehicle with information acquired from various sensors, without the intervention of the driver, until the vehicle reaches to its destination. In this paper, our focus is on developing an unmanned conveyance system by exploiting low-cost sensing technology for indoor factories or warehouses, where the moving range of the vehicle is limited. To this end, we propose an architecture of a scalable automated conveyance system. Our proposed system includes a number of unmanned conveyance vehicles, and the efficient control mechanism of the vehicles without neither conflicts nor deadlock between the vehicles being simultaneously moved. By implementing the real prototype of the system, we successfully verify the efficiency and functionality of the proposed system.

• 중국학논총
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• no.72
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• pp.101-122
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• 2021

Over the past 20 years, labor standards have been widely used in free trade agreements. The U.S., the European Union and China have all aggressively signed free trade agreements with their trading partners, developing different styles on labor standards. According to the study, the implementation of the KOREa-EU FREE trade agreement has been hampered by ongoing disputes over the terms of the FREE trade agreement and the ILO since the korea-EU free trade agreement was signed. Because in order to break this deadlock, relevant scholars have done a lot of research, but mainly focused on the economic and trade field. Therefore, this paper for the first time systematically studies the substantive focus of disputes over FTA and ILO clauses, and carefully analyzes the domestic law amended by South Korea, and provides suggestions and inspirations for China by drawing lessons from the revision model of South Korea's domestic law. This is from a newperspective: the essence of the korea-EU FTA and ILO disputes is the conflict between international law and domestic law, and the conflict between free trade agreements and human rights protection. It holds that the essence of disputes should be sorted out from the perspective of legal principles and human rights protection, and the free trade and human rights protection should be actively coordinated. In order to make China more actively integrate into the international economy, China should adopt a positive attitude to revise and perfect its own laws, so as to realize the purpose of common development of international trade and human rights protection.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.407-416
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• 2022

Multiple AMRs have been proved to be effective in improving warehouse productivity by eliminating workers' wasteful walking time. Although Multi-agent Path Finding (MAPF)-based solution is an optimal approach for this task, its deployment in practice is challenging mainly due to its imperfect plan-execution capabilities and insufficient computing resources for high-density environments. In this paper, we present a MAPF-based fleet management system architecture that robustly manages multiple robots by re-computing their paths whenever it is necessary. To achieve this, we defined four events that trigger our MAPF solver framework to generate new paths. These paths are then delivered to each AMR through ROS2 message topic. We also optimized a graph structure that effectively captures spatial information of the warehouse. By using this graph structure we can reduce computational burden while keeping its rescheduling functionality. With proposed MAPF-based fleet management system, we can control AMRs without collision or deadlock. We applied our fleet management system to the real logistics warehouse with 10 AMRs and observed that it works without a problem. We also present the usage statistic of adopting AMRs with proposed fleet management system to the warehouse. We show that it is useful over 25% of daily working time.

• Journal of Internet Computing and Services
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• v.1 no.2
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• pp.11-18
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• 2000

In this paper we present a new extensible model based upon the concept of subtransactions in real-time transaction systems. The nested transaction model originally proposed by J. Moss is extended for real-time uniprocessor transaction systems by adding explicit timing constraints. Based upon the model, an integrated concurrency control and scheduling algorithm is developed, that not only guarantees timing constraints of a set of real-time transactions but also maintains consistency of the database. The algorithm is based on the priority ceiling protocol of Sha et al. We prove that the Real-Time Nested Priority Ceiling Protocol prevents unbounded blocking and deadlock, and maintains the serializability of a set of real-time transactions. We use the upper bound on the duration that a transaction can be blocked to show that it is possible to analyze the schedulability of a transaction set using rate-monotonic priority assignment. This work is viewed as a step toward multiprocessor and distributed real-time nested transaction systems. Also, it is possible to be extended to include the real-time multimedia transactions in the emerging web-based database application areas.